Search results for "Rest"
showing 10 items of 8829 documents
Bush pig (Potamochoerus porcus) seed predation of bush mango (Irvingia gabonensis) and other plant species in Democratic Republic of Congo.
2012
4 pages; International audience
Periphyton support for littoral secondary production in a highly humic boreal lake
2016
Steep stratification and poor light penetration in highly humic lakes typically restrict oxygenated littoral areas to narrow lake margins. However, in some instances, surrounding floating vegetation mats can sustain highly productive periphyton and more diverse invertebrate communities than pelagic areas. Little is known about how these littoral food webs function or the extent to which the pelagic and littoral food webs are coupled. We added 15N-labeled ammonium nitrate to the floating moss mat surrounding the littoral zone of Mekkojärvi, a small highly humic and fishless lake in southern Finland. Our goal was to increase the δ15N values of periphyton to investigate the diets of littoral i…
Potential of Crotalaria species as green manure crops for the management of pathogenic nematodes and beneficial mycorrhizal fungi
2004
On the basis of preliminary experiments, some Crotalaria species from Senegal were investigated to determine (1) their susceptibility to Meloidogyne javanica and M. incognita compared to a sensitive host (tomato), (2) their mycorrhizal and rhizobial responses, and (3) the effect of their cultivation on the mycorrhizal soil infectivity. The nematode invasion rates on Crotalaria spp. ranked from 0.17 to 7.17% and from 0.58 to 5.25%, respectively, for M. incognita and M. javanica, vs. 97% and 77% on tomato. Moreover, the inoculated J2 which invaded tomatoes developed into adult females, while those on Crotalaria spp. rarely developed beyond the third stage, confirming that all Crotalaria spp. …
The value of by-catch data: how species-specific surveys can serve non-target species
2019
Camera trapping has a wide range of research application, but, while research designs are often focused on the study of a single focal species, cameras can also record other non-target species. Occupancy modeling using by-catch data can be a valuable resource to gain information on these species maximizing the scientific effort and efficiency of wildlife surveys. In this study, we used by-catch data from a European wildcat (Felis silvestris silvestris) survey in Southern Italy to assess the habitat covariates determinant for the occupancy of the crested porcupine (Hystrix cristata). We recorded 33 detections at 17 out of 51 cameras (naive occupancy = 0.33). The best models fitted the data w…
No growth stimulation of Canada’s boreal forest under half-century of combined warming and CO 2 fertilization
2016
Considerable evidence exists that current global temperatures are higher than at any time during the past millennium. However, the long-term impacts of rising temperatures and associated shifts in the hydrological cycle on the productivity of ecosystems remain poorly understood for mid to high northern latitudes. Here, we quantify species-specific spatiotemporal variability in terrestrial aboveground biomass stem growth across Canada’s boreal forests from 1950 to the present. We use 873 newly developed tree-ring chronologies from Canada’s National Forest Inventory, representing an unprecedented degree of sampling standardization for a large-scale dendrochronological study. We find significa…
Spatial distribution of saplings in heavily worn urban forests: Implications for regeneration and management
2012
Abstract We studied the spatial distribution of saplings in the vicinity of other saplings and mature trees in heavily worn urban forests. Our aim was to identify favorable microsites for saplings to regenerate under different levels of wear. We hypothesized that these safe microsites were situated close to tree trunks that might offer shelter from trampling caused by humans and their pet dogs. The distribution of saplings was explored at 0.1–0.6 m to the nearest sapling and 0.1–2 m to the nearest mature tree. Sorbus aucuparia was the most abundant sapling species, followed by Populus tremula , Betula pubescens and Picea abies . These species all tended to cluster with their conspecific sap…
Vibration Monitoring of the Mechanical Harvesting of Citrus to Improve Fruit Detachment Efficiency
2019
The introduction of a mechanical harvesting process for oranges can contribute to enhancing farm profitability and reducing labour dependency. The objective of this work is to determine the spread of the vibration in citrus tree canopies to establish recommendations to reach high values of fruit detachment efficiency and eliminate the need for subsequent hand-harvesting processes. Field tests were carried out with a lateral tractor-drawn canopy shaker on four commercial plots of sweet oranges. Canopy vibration during the harvesting process was measured with a set of triaxial accelerometer sensors with a datalogger placed on 90 bearing branches. Monitoring of the vibration process, fruit pro…
Response of the N and P cycles of an old-growth montane forest in Ecuador to experimental low-level N and P amendments
2010
Abstract Atmospheric nitrogen (N) and phosphorus (P) depositions are expected to increase in the tropics as a consequence of increasing human activities in the next decades. In the literature, it is frequently assumed that tropical montane forests are N-limited, while tropical lowland forests are P-limited. In a low-level N and P addition experiment, we determined the short-term response of N and P cycles in a north Andean montane forest on Palaeozoic shists and metasandstones at an elevation of 2100 m a.s.l. to increased N and P inputs. We evaluated experimental N, P and N + P additions (50 kg ha −1 yr −1 of N, 10 kg ha −1 yr −1 of P and 50 kg + 10 kg ha −1 yr −1 of N and P, respectivel…
Spatial Variation of Leaf Optical Properties in a Boreal Forest Is Influenced by Species and Light Environment
2017
Leaf Optical Properties (LOPs) convey information relating to temporally dynamic photosynthetic activity and biochemistry. LOPs are also sensitive to variability in anatomically related traits such as Specific Leaf Area (SLA), via the interplay of intra-leaf light scattering and absorption processes. Therefore, variability in such traits, which may demonstrate little plasticity over time, potentially disrupts remote sensing estimates of photosynthesis or biochemistry across space. To help to disentangle the various factors that contribute to the variability of LOPs, we defined baseline variation as variation in LOPs that occurs across space, but not time. Next we hypothesized that there wer…
Effects of stand-level and landscape factors on understorey plant community traits in broad-leaved forest of the boreo-nemoral zone in Latvia
2019
Abstract Knowledge of the limiting processes shaping the composition of plant communities of woodland is important in conservation of biological diversity. The aim of our study was to examine the effect of stand-level factors (soil and canopy composition, age and area) and landscape factors (fragmentation of broad-leaved forest, distance to a historical manor house, and past history) on plant community trait composition in broad-leaved forest. We hypothesized that the plant functional community is shaped by both dispersal filtering due to landscape factors and by environmental characteristics. We recorded all vascular plants, described canopy composition and estimated soil characteristics i…